Wife Swapping

The two guys, Jack and Bill, have decided to try to persuade their wives to have a bit of partner swapping for the night.

The guys have agreed that if they can pull off the wife swap, when they sit around the breakfast table the following morning, they will tap their teaspoon on the side of their coffee mug the number of times that they did it with each other's wives. Clever enough!

After several drinks that night they succeed! Jack knows it's that time of the month for his wife and the thought of Bill not knowing this makes him smile.

The next morning they are all at the breakfast table, slightly hangover and quite uncomfortable, when Jack proudly taps his teaspoon 3 times against his coffee mug.

After a brief moment of thinking, Bill takes his teaspoon and taps it once on the strawberry jam and 3 times on the peanut butter.